{"product_id":"lewmar-559017a-alloy-shear-pin-for-185tt-bow-thruster","title":"Lewmar 559017A Alloy Shear Pin for 185TT Bow Thruster (2-Pack)","description":"\u003cp class=\"nvn-hero\"\u003eThis is the Lewmar 559017A alloy shear pin, the small sacrificial part that protects your 185TT bow thruster when the prop hits something it shouldn't. It comes as a pack of two, so you've always got a spare in the toolbox. Cheap insurance for an expensive thruster.\u003c\/p\u003e\n\n\u003cdiv class=\"nvn-description\"\u003e\n\u003cp\u003eEvery bow thruster needs a weak point, and on the Lewmar 185TT that weak point is this pin. The 559017A is an alloy shear pin, and its whole job is to break before anything expensive does. When the thruster prop catches a dock line, a stray stick, a rope, or a thick mat of weed, the load has to go somewhere. Without a shear pin it goes straight into the drive and the motor. With one, the pin snaps first and saves the rest.\u003c\/p\u003e\n\u003cp\u003eThink of it as a fuse for the mechanical side of your thruster. The prop connects to the drive through this pin. Under normal thruster use it transmits plenty of torque to push your bow around in a crosswind or a tight slip. But hit a hard jam and the alloy gives way at a predictable point, letting the prop stop while the motor keeps turning free. You lose thrust until you replace the pin, but you don't lose a gearbox or a motor. That's the trade, and it's a good one.\u003c\/p\u003e\n\u003cp\u003eLewmar makes this one from alloy, which shears cleanly under a sudden overload. It's the sacrificial part of the system, so it's meant to be replaced. Boaters who run bow thrusters in weedy water or shallow, debris-filled harbors go through them, and that's normal. A sheared pin isn't a failure of the thruster. It's the pin doing exactly what Lewmar designed it to do.\u003c\/p\u003e\n\u003cp\u003eThis part is specific to the 185TT tunnel thruster. It works with both the 12V and the 24V 185TT motors. It is not the pin for the larger 250TT, so if you run that bigger thruster this isn't your part. Check the model plate on your thruster before you order. The 185 is common on cruising sailboats in roughly the 28 to 35 foot range, and if you've got one, this is the drive pin it takes.\u003c\/p\u003e\n\u003cp\u003eHow do you know you've sheared it? The giveaway is a thruster that sounds like it's running, the motor hums, but the boat's bow doesn't move. No thrust, plenty of noise. That's a sheared pin almost every time. The fix is straightforward mechanically, but on most 185TT installs there's no access port, so you'll be pulling the propeller to reach the pin and swap it. Plan the job for a haul-out or a calm day at the dock rather than mid-docking with wind pushing you onto the pilings.\u003c\/p\u003e\n\u003cp\u003eWhen you put the new pin in, a lot of installers give the pin ends a light film of grease and nothing more. A dry fit can bind on reassembly, and too much grease just makes a mess and traps grit. Light touch on the ends, seat it, reassemble the prop, and you're back in business. If you boat in salt water, keep an eye on the pin over the season. Alloy corrodes faster than stainless out there, so coastal cruisers tend to carry spares and check the pin as part of routine service.\u003c\/p\u003e\n\u003cp\u003eWhich is exactly why Lewmar sells the 559017A as a pack of two. One to fix the problem you've got, and one to stash in the spares kit for next time. If you cruise anywhere with floating weed, current-borne debris, or crab-pot lines, next time is a question of when, not if. Having a spare pin and a few basic tools aboard turns a stuck bow into a fifteen-minute job instead of a ruined afternoon.\u003c\/p\u003e\n\u003cp\u003eBottom line, this is cheap insurance for a pricey piece of gear. The thruster itself, the motor, the gear leg, all of it costs real money. This pin costs a few dollars and stands between a minor prop strike and a major repair bill. Buy the genuine Lewmar part, keep the spare aboard, and your 185TT keeps doing its job season after season.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul class=\"nvn-features\"\u003e\n  \u003cli\u003eAlloy shear pin engineered as the sacrificial link in the Lewmar 185TT bow thruster drive\u003c\/li\u003e\n  \u003cli\u003eShears cleanly under a sudden overload, so the pin breaks before the motor or gearbox does\u003c\/li\u003e\n  \u003cli\u003eSized specifically for the 185TT tunnel thruster in both 12V and 24V versions\u003c\/li\u003e\n  \u003cli\u003eSold as a 2-pack, one to fix the current shear and one to keep in your spares kit\u003c\/li\u003e\n  \u003cli\u003eGenuine Lewmar part, MPN 559017A, for a correct fit and clean shear behavior\u003c\/li\u003e\n  \u003cli\u003eNot for the larger 250TT thruster, which keeps you from a wrong-fit install\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cdiv class=\"nvn-trust\"\u003e\n  \u003ch2\u003eWhy Buy from NVN Marine\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003eAuthorized Lewmar reseller, full manufacturer warranty\u003c\/li\u003e\n    \u003cli\u003eNMEA member and ABYC certified, advice from real boat techs\u003c\/li\u003e\n    \u003cli\u003eSame-day shipping before 3 PM ET on in-stock items\u003c\/li\u003e\n    \u003cli\u003eNY headquarters and Fort Lauderdale flagship retail store\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003cdiv class=\"nvn-faq\"\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat does the shear pin actually do?\u003c\/summary\u003e\n    \u003cp\u003eIt's the sacrificial link between the thruster prop and the drive. If the prop hits a line, a stick, or a mat of weed, the alloy pin shears first and stops the prop, which spares the motor and gearbox from the shock load. You lose thrust until you swap it, but you don't lose the expensive parts.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhich thruster does the 559017A fit?\u003c\/summary\u003e\n    \u003cp\u003eThe Lewmar 185TT tunnel thruster, in both its 12V and 24V versions. It is not the pin for the larger 250TT, so check your thruster's model plate before ordering.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eIs this the alloy pin or the stainless one?\u003c\/summary\u003e\n    \u003cp\u003eThis is the alloy version, part number 559017A. Lewmar builds it to shear cleanly under overload. If you boat in salt water, keep in mind that alloy corrodes faster than stainless, so check the pin during routine service.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eHow many pins come in the pack?\u003c\/summary\u003e\n    \u003cp\u003eTwo. Lewmar sells the 559017A as a 2-pack, so you can fix the current shear and still have a spare aboard for next time.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eHow do I know the pin has sheared?\u003c\/summary\u003e\n    \u003cp\u003eThe classic sign is a thruster that hums like it's running but produces no thrust. Plenty of motor noise, no push at the bow. That's almost always a sheared pin.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eDo I have to remove the propeller to replace it?\u003c\/summary\u003e\n    \u003cp\u003eOn most 185TT installs, yes. There's usually no access port, so you'll pull the prop to reach the pin and swap it. It's best done at a haul-out or on a calm day at the dock.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eShould I grease the pin when I install it?\u003c\/summary\u003e\n    \u003cp\u003eA light film of grease on the pin ends helps. A dry fit can bind on reassembly. Skip the heavy grease, since too much just traps grit.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eShould I keep spares aboard?\u003c\/summary\u003e\n    \u003cp\u003eYes, especially if you cruise coastal water or anywhere with floating weed and debris. A spare pin and a few basic tools turn a stuck bow into a quick fix instead of a ruined afternoon.\u003c\/p\u003e\n  \u003c\/details\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\n\u003ctable class=\"nvn-specs\"\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n\u003cth\u003eTitle\u003c\/th\u003e\n\u003ctd\u003eLewmar 559017A Alloy Shear Pin for 185TT\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eBrand\u003c\/th\u003e\n\u003ctd\u003eLewmar\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eManufacturer Part Number\u003c\/th\u003e\n\u003ctd\u003e559017A\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eUPC\u003c\/th\u003e\n\u003ctd\u003e743683005466\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eCategory\u003c\/th\u003e\n\u003ctd\u003eBow Thrusters\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eProduct Type\u003c\/th\u003e\n\u003ctd\u003eBow Thruster Spare Part\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eMaterial\u003c\/th\u003e\n\u003ctd\u003eAlloy\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eSold As\u003c\/th\u003e\n\u003ctd\u003ePack of 2\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eComponent Type\u003c\/th\u003e\n\u003ctd\u003eSacrificial Shear Pin\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eCompatible Thruster\u003c\/th\u003e\n\u003ctd\u003eLewmar 185TT\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eVoltage Compatibility\u003c\/th\u003e\n\u003ctd\u003e12V and 24V\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eFunction\u003c\/th\u003e\n\u003ctd\u003eProtects thruster drive under load\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003cscript type=\"application\/ld+json\"\u003e\n{\n    \"@context\": \"https:\/\/schema.org\",\n    \"@type\": \"FAQPage\",\n    \"mainEntity\": [\n        {\n            \"@type\": \"Question\",\n            \"name\": \"What does the shear pin actually do?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"It's the sacrificial link between the thruster prop and the drive. If the prop hits a line, a stick, or a mat of weed, the alloy pin shears first and stops the prop, which spares the motor and gearbox from the shock load. You lose thrust until you swap it, but you don't lose the expensive parts.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Which thruster does the 559017A fit?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"The Lewmar 185TT tunnel thruster, in both its 12V and 24V versions. It is not the pin for the larger 250TT, so check your thruster's model plate before ordering.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Is this the alloy pin or the stainless one?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"This is the alloy version, part number 559017A. Lewmar builds it to shear cleanly under overload. If you boat in salt water, keep in mind that alloy corrodes faster than stainless, so check the pin during routine service.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"How many pins come in the pack?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"Two. Lewmar sells the 559017A as a 2-pack, so you can fix the current shear and still have a spare aboard for next time.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"How do I know the pin has sheared?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"The classic sign is a thruster that hums like it's running but produces no thrust. Plenty of motor noise, no push at the bow. That's almost always a sheared pin.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Do I have to remove the propeller to replace it?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"On most 185TT installs, yes. There's usually no access port, so you'll pull the prop to reach the pin and swap it. It's best done at a haul-out or on a calm day at the dock.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Should I grease the pin when I install it?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"A light film of grease on the pin ends helps. A dry fit can bind on reassembly. Skip the heavy grease, since too much just traps grit.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Should I keep spares aboard?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"Yes, especially if you cruise coastal water or anywhere with floating weed and debris. A spare pin and a few basic tools turn a stuck bow into a quick fix instead of a ruined afternoon.\"\n            }\n        }\n    ]\n}\n\u003c\/script\u003e\n","brand":"Lewmar","offers":[{"title":"Default Title","offer_id":44785936597085,"sku":"1004640","price":13.79,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0299\/7266\/0317\/files\/LEW559017A_001.jpg?v=1784944616","url":"https:\/\/nvnmarine.com\/products\/lewmar-559017a-alloy-shear-pin-for-185tt-bow-thruster","provider":"NVN Marine","version":"1.0","type":"link"}